No matter how a raw foie gras is to be prepared, it should first be rinsed in cold water and examined closely for green spots. These are caused by bile; they must be cut or scraped away because the bile has a strong, bitter taste. Also, if there are any bits of external fat, remove them.
Next, the liver should be soaked. (This step is not required, but it does improve the product.) Place it in lightly salted ice-cold water or milk to cover. Let stand for up to 2 hours, no longer. Remove from the salted liquid and rinse in fresh, cold water.